Catalytic hydrogenation process



Patented Apr. 20, 1937 I I UNITE-D STATES-PATENT OFFlCE CATALYTICHYDROGENATION PROCESS Wilbur Arthur Lazler, Elmhurst, DeL, assignor toE. I. du Pont de Nemours & Company, Wilmington, Del., a corporation ofDelaware No Drawing. Application May 27, 1930,

I Serial No. 456,298

29 claims. (01. 260-54) This invention relates tocatalytic processes,tofore b n mpl y d r hydr e nat ns i th and more particularly toprocesses for the liquid liquid P phase hydrogenation of carboncompounds by This invention accordingly has as an object means ofmetallic hydrogenating catalysts preto P v de a process for the hy ronati n of s pared by the reduction, or ignition and reduction, r n mp uds in the iq p s y th us of chromates, molybdates, and similar salts. ofhighly fl fl hydrtlgenating metal Cata ysts Considerable work has beendone in the field P p y Iedllfiing a Composition p i g of catalyticchemistry with a view to developing l Oxide Of a hydmgenating metal Ombed improved catalysts for the hydrogenation of such with a more acidiflOxide Such as chromflte,

10 unsaturated compounds as theolefins, unsatumolybdiite, Similar Salt-A further O j t is 10 rated fats and fatty acids, benzene and its det vd u a p ss v lvin th use of rerivatives, and a large number of othercompounds dulled l e y rogenating cataly 0f the containing unsaturatedfunctions, such as th above type. A specific object is to carry out thealdehydes, nitriles, amides, and heterocycllc un liquid p as yd at f aic mp unds saturated rings. Most of this work has been capable of yd a nby t us f ta ysts 15 based upon the classical discovery of Sabatierprepared by reducing ke aiie t0 cke that finely divided metallic nickelis capable of chromite by means of the action of heat alone or causingthe union of hydrogen with these cornheated hydrogen, g o f t e oh omatepounds. The method ha b further expanded to chromite, followed by afurther reduction of and supplemented by the work of Ipatief on the atleast a port of the nickel compounds to 20 application of high pressuresto these reactions. mentary nickel Extensive research has been carriedout here- A Preferred Object of h invention relates t tofore with theresult that several different meththe hydrogenation of fllrfllral, P aly in a ods for the prepartion of hydrogenation catalyst liquid phase,in the presence of catalysts containhave been'developedthe most commonof which mg chromites 0f hydrogenating metal Catalysts 5 involve theprecipitation and reduction of nickel These Objects are aCOOmplished ythe fo w hydroxide or carbonate, the reduction of nickel mg invention, wc in its general aspects, comoxide prepared by ignition ofthe nitrate,anodic prises the employment in liquid- Dhafie hydro" oxidation followedby reduction, heating certain genations of catalysts P p either by oranic lt of nickel t their decomposmon ing a salt consisting of acombination of an oxide 30 temperature, and electrochemical depositionof Of e of the hydrogenating metals, such as metalli ni k t nickel,copper, cobalt, and iron, with a more Furth 7 various th of reductionacidic oxide, such as one of the oxides of the elehave been proposed,ranging from t ordingmy merits contained in the fifth and sixth groupsof dry reduction with hydrogen to reduction in an the Periodic Tabletypified by chromium; by 35 inert liquid vehicle or in the presence ofthe oil first igniting one of these Salts to form an Oxide or othersubstance undergoing hydrogenation. composition containing chromiummolybde" As is well known, these catalysts have found exnum in trivalentform and then reducing this tensive use in the commercial hydrogenationof compound- Ignition of the combined Salt '40 fat oils, and Similarreadily hydrogenated o convert the metal of the more acidic oxide to a40 stanooo I have f und however, that in general lower valenceconstitutes a species of reduction, catalysts prepared by th abovemethods further reduction of the salt being accomplished thoughordinarily suitable for the hydrogenation by Contact with hydrogen- Theobject of the of fats and oils, may be entirely inadequa for duction byhydrogen in either case is toobtain the more dimoult hydrogenation ofsuch the hydrogenatlng component in the form of a 45 ounds as aldehydes,ketones, sugars, phenols, finely divided and highly active metal ormetallic furfural and its derivatives, or benzene and oxide I m i lpyridine and their homologues. Although many sgz i ggf gfi zg gg az figsggfxzggggY r types of nickel catalysts have been used for vari liquid orvapor phase hydrogenation so ififiiilfe siiiii ci ifefit $21333? TFESTZ? far as I am aware pure alkau'free nickel catation. These catalystsmay be said to consist of lysl; pr p by the reduction, ignition and .ahydrogenating metal or its oxide either assosubsequent reduction, ofchromate's, molybdates, ciate'd or combined with a more acidic metallicor othercompounds of this type, has never hereoxide. By the termhydrogenating metal, I re- 55 lead, and bismuth.

It has just been stated that the hydrogenating metals are combined orassociated with acidic metallic oxides. By the term acidic oxides Irefer to those of elements contained in the fifth and sixth groups ofthe Periodic Table, for example, oxides of chromium, molybdenum,tungsten, vanadium, uranium, and titanium. Among the salts which areespecially suitable for the preparation of the hydrogenating catalystsof this invention may be mentioned the chromates and molybdates. Thesecompounds may be prepared by precipitation, fusion, or in other wayswell known to those skilled in the art. It is to be noted, however, thattreatment of solutions of nickel salts with an equivalent amount of analkali metal chromate according to prior art practice yields aprecipitate of basic nickel chromate that always contains alkali metalchromate which can be leached out only after heating at a temperaturesuflicient to destroy the nickel chromate.

I Certain of the nickel-chromium compounds constitute a convenientstarting point from which to prepare efflcient hydrogenating catalystsaccording to the principles of this invention. I have described belowseveral typical methods for the preparation of catalyst compositions inaccordance with the principles of my invention.

Taking the preparation of nickel chromite catalysts as typical of thecompositions of my invention, it may be stated that there are twogeneral methods of preparation, (1) reduction of a chromate withhydrogen, or (2) ignition of a chromate, to a chromite followed byreduction. When prepared by either of these methods the nickel chromateis first converted to a chromite composition which may be considered toconsist of nickel oxide (MO) and nickel chromite (NiCr2O4) in whichchromium is in the trivalent form. This composition is then furtherreduced to a composition consisting of metallic nickel, nickel oxide,and nickel chromite.

In order to classify these compounds under a generic term regardless oftheir method of preparation, they may be designated nickel-chromiumoxide catalysts, or nickel chromites; However, by the term chromite I donot intend to define these compositions as definite chemical compounds,but as compositions in which the catalytically active component is ahydrogenating metal which may be either combined or associated with amore acidic oxide in a lower stage of oxidation. The hydrogenating metalmay exist, either in the metallic form or as an oxide, or

both, the chemical relationships of the various elements of thecomposition depending to a cer-' tain extent upon the methods ofpreparation and reduction'employed. According to my preferred methods ofp eparation the total nickel oxide component of the chromite is onlypartiallyreduced with the result that the composition contains, asindicated above, three components, 1. e., finely divided,v reduced,metallic nickel, nickel oxide, and nickel chromite.

The following typical methods have been found suitable for thepreparation of chromite catalysts and especially for their preparationin an alkali-free condition: I

(1) Sodium chromate and nickel sulphate solutions are allowed to reactto form a brown precipitate of basic nickel chromate containing somesodium chromate. The resulting solution is filtered and the precipitatewashed, dried, and ignited at a mild red heat. The washing of theprecipitate removes the greater portion of the sodium chromate andnickel sulfate carried down by the precipitate. However, the sulfate ionis extremely difiicult to eliminate, and the washing step, even when theprecipitate is thoroughly washed, leaves traces of sulfate in the washedprecipitate. After cooling, the black residue containing partiallycombined nickel oxide and chromium oxide'is extracted with hot water toremove any remaining alkali chromate. This oxide mixture is then reducedwith hydrogen.

(2) Nickel oxide or carbonate is digested with chromic acid untilcompletely dissolved. On evaporating the solution to dryness, theresidue is reduced with hydrogen, or is first heated to redness,representing a temperature in the vicinity of 800 C., to convert it tothe chromite form, followed by hydrogen reduction.

These compositions, typified by the chromates, may be ignited attemperatures ranging preferably from GOO-800 0., although highertemperatures may be employed in special cases. Reduction of the ignitedcomposition is then carried out preferably at a temperature of 500 C.The chromate may also be reduced directly at 500 C. without previousignition, but I prefer to first ignite the material since the resultingcatalyst is more compact and convenient to handle. During the ignitionof the class of compounds exemplified by the chromates, the chromium orlike metal is reduced to the trivalent form, the nickel remaining atthis stage of the preparation as nickel oxide. Further reduction bymeans of hydrogen reduces at least a part of the combined nickel to theactive metallic form. It is also to be noted that simple hydrogenreduction of the chromate itself will eventually accomplish the sameresult.

I prefer to reduce salts of the ferrous metal group with hydrogen attemperatures of from 400600 C., preferably at 500 ,0. Somewhat lowertemperatures suflice for reduction of the non-ferrous hydrogenatingmetals.

The proposed methods of catalyst preparation have several advantages.Not only is the catalyst very active, but it is also more capable ofwith the materials of this invention lend themselves very readily tocompression into a form that may be used in a continuous operationwherein the liquid to be hydrogenated is permitted to flow over thecontact mass in the presence of hydrogen under pressure. Nickel andcopper chromites, for example, are readily briquetted with the ordinarytypes of pharmaceutical tablet machinery without injury to the porosityor activity of the catalyst. It will be apparent that a continuousmethod of operation employing the catalysts of this invention ofiersmany advantages over the usual autoclave process.

Having outlined above the general principles l pared by the highpressure dehydrogenatlon'of of my invention, the following exampleswhich are included merely for purposes of illustration and not as alimitation, disclose specific methods used in carrying the inventioninto practice and the improved results accruing from its use.

Example 1.--228 grams of pure nickel hydroxide was suspended in waterand treated with 200 grams of chromic anhydride. The resulting paste wasfiltered, dried and ignited four hours at 400 C. 5 grams of the residualnickel chromite composition was reduced 24 hours with hydrogen at 500 C.The resulting mass was cooled and transferred without exposure to air toa vessel containing 200 cc. of crude synthetic higher alcohols (boilingrange 135 C.) preethanol and containing, in addition to butanol, about20% of unsaturated compounds such as crotonyl alcohol and 30-40% ofesters including butyl acetate and ethylbutyrate. After agitating themixture for two hours at C. under a hydrogen pressure of 400 pounds, theiodine number of the mixture had drOpped from 99 to 33, indicatingsaturation of the compounds containing unsaturated bonds, with aresultant improvement in the quality of the product for solventpurposes.

Example -2.--290 grams of nickel nitrate was dissolved in two liters ofwater and treated with an equal volume of water containing 194 grams ofpotassium chromate. The mixture was heated to 90 C. and treated with asolution contain ing 56 grams of potassium hydroxide. The precipitatewas decanted, washed, dried, and heated at a dull red heat for -fourhours, after which it was cooled and again washed to free it from thelast of the potassium chromate set free by the ignition. 10 grams ofthis alkali-free nickelchromium oxide composition was then reduced withhydrogen at 500 C. and employed for the hydrogenation of cotton seedoil. After stirring 200 cc. of the oil with the reduced catalyst at 170C. under 600 pounds hydrogen pressure for one hour, the melting point ofthe fat was found to have been raised to 65 C.

Example 3.Mesityl oxide agitated for two hours in the presence of anickel-chromium oxide catalyst prepared by the reduction of nickelchromate as described in method 2 above under a hydrogen pressure of1700 pounds. Hydrogen began to be absorbed at 140 C. and the reactionbecame rapid at -180 C. After cooling and separating the catalyst fromthe liquid products, 75% of the liquid distilled at 1l8-12l 0., theboiling point of methyl isobutyl ketone.

Example 4.--An 85% solution of phenol in water was charged into a highpressure autoclave with such an amount of the nickel-chromium oxidecatalyst, prepared as indicated in Example 1, as contained elementarynickel equal to 1% of the phenol treated. The mixture was heated andagitated for two hours with pure hydrogen at 800 pounds pressure.Hydrogenation began at 120 C. and was quite rapid at C.

one of the metal Example 6.Nickel molybdate was formed by treating awarm dilute solution of nickel nitrate. with a solution containing anequivalent amount of ammonium molybdate. The acid formed duringthe'reaction was neutralized by the addition of ammonium hydroxide. Theprecipitate was then filtered, washed, dried and reduced with hydrogenat 450 C. 150 grams of mesityl oxide was shaken with 5 grams of thereduced catalyst under 1500 pounds hydrogen pressure for three hours at150 C. The product was cooled and distilled. The boiling point was foundto be 115-120 C. indicating practically quantitative conversion tomethyl isobutyl ketone.

The above examples illustrate applications of the improved catalysts ofmy invention to certain typical liquid phase hydrogenations, but it isto be understood that they may be employed in many other reactions ofthis general class. For example, crude metacresol, known commercially ascresylic acid, may be effectively hydrogenated at about 200 0., usingthe same catalyst as in will, of course, vary considerably with thecompound to be treated and the particular catalyst selected for anygiven reaction. As many apparently and widely different embodiments ofthis invention may be made with out departing from the spirit and scopethereof, it is to be understood that I do not limit myself to thespecific embodiments thereof except as defined in the appended claims.

I claim:

1. In a catalytic process of hydrogenating an organic compound capableof hydrogenation, the step which comprises contacting said compound inthe liquid state, in the presence of hydrogen, with a catalystcomprising essentially an oxide of a metal selected from the groupconsisting of iron, nickel, cobalt, copper, silver, tin, cadmium, lead,and bismuth chemically combined with an oxide of a metal selected fromthe group consisting of chromium, molybdenum, tungsten, vanadium, anduranium, said catalyst being prepared by partially reducing acomposition in which at least oxides are in a higher state of oxidation.

2. In the process of hydrogenating an unsaturated organic compound inthe liquid phase, the

step which comprises bringing a mixture of said compound in'the liquidstate and hydrogen into contact with a catalyst comprising essentiallyan oxide of a metal selected from the group consisting of iron, nickel,cobalt, copper, silver, tin, cadmium, lead, and bismuthchemicallycombined with an oxide of a metal selected from the group consisting ofchromium, molybdenum, tungsten,

vanadium, and uranium, said catalyst being pre-=- pared by partiallyreducing. a composition in which at least one of the metal oxides are ina. higher state of oxidation.

3. The process of claim 2 in which the catalyst is an alkali-freecomposition prepared by partially reducing a chromate of a hydrogenatingmetal.

4. The process of claim 2 in which the catalyst 5 is an alkali-freecomposition prepared by heating a chromate of a hydrogenating metal toform a chromite and partially reducing said chromite.

5. The process of claim 2 in which the catalyst is an alkali-freecomposition prepared by heat-- ing nickel chromate to form nickelchromite and partially reducing said nickel chromite with hydrogen.

6. The process of claim 2 in which the catalyst is an alkali-freecomposition prepared by heating l5 nickel chromate at a temperature ofat least 500 C. and reducing the ignited composition in hydrogen at atemperature of 400-500 C.

7. The process of hydrogenating crude synthetic butyl alcohol preparedby the pressure dehydrogenation of ethanol and containing unsaturatedorganic compounds, which comprises agitating said alcohol with hydrogenunder a pressure of 400 pounds at a temperature of 150 C. in thepresence of a catalyst prepared by heating nickel chromate at atemperature of 400 C. and then partially reducing the chromite withhydrogen at 500 C.

8. The process of hydrogenating an organic compound which isstructurally capable of hydrogenation which comprises contacting suchcompound in the liquid phase in the presence of hydrogen with a catalystcomprising essentially a chromite of a hydrogenating metal selected fromthe group consisting of iron, nickel, cobalt, copper,

silver, tin, cadmium, lead and bismuth.

9. The process of hydrogenating an organic compound which isstructurally capable of hydrogenation which comprises contacting suchcompound in the liquid phase in the presence of hydrogen with a catalystcomprising essentially a chromite of a hydrogenating metal selected fromthe group consisting of iron, nickel, cobalt, copper, silver, tin,cadmium, lead and bismuth prepared by partially reducing thecorresponding chromate.

' 10. The process described in claim 2 in which the catalyst ispreparedby partially reducing a chromate of a hydrogenating metalselected from the group consisting of iron, nickel, cobalt, copper,

50 silver, tin, cadmium, lead, and bismuth.

' 11. The process described in claim 2 in which the catalyst is preparedby partially reducing a chromate of a hydrogenating metal selected fromthe group consisting of iron, nickel, cobalt, copper, silver, tin,cadmium, lead, and bismuth by heating it to its decompositiontemperature.

12. The process described in claim 2 in which the catalyst is preparedby" partially reducing copper chromate.

60 13. The process described in claim 2 in which the catalyst isprepared by partially reducing copper chromate by heating the copperchromate to its decomposition temperature.

. 14. The process of hydrogenating furfural 65 which comprises reactingfurfural and hydrogen in the presence of a catalyst prepared bypartially reducing a composition comprising essentially an oxide of ahydrogenating metal selected from the group consisting of iron, nickel,cobalt, cop- 70 per, silver, tin, cadmium, lead, and bismuth combinedwith an oxide of a metal selected from the group consisting of chromium,molybdenum, tungsten, vanadium, and uranium.

15. The process of' hydrogenating furfural 75 which comprises reactingfurfural in the liquid state and hydrogen in the presence oi. a catalystprepared by partially reducing a composition comprising essentially anoxidc'of a hydrogenat ing metal selected from the group consisting ofiron, nickel, cobalt, copper, silver, tin, cadmium,

lead, and bismuth combined with an oxide of a sentially an oxide of ahydrogenating metal selected from the group consisting of iron, nickel,cobalt, copper, silver, tin, cadmium, lead, and bismuth combined with anoxide of a metal selected from the group consisting of chromium,molybdenum, tungsten, vanadium and uranium, under a superatmosphericpressure and at a temperature in excess of 80 C.

17. The process of hydrogenating furfural which comprises reactingfurfural in the liquid state and hydrogen in the presence/of a catalystprepared by partially reducing a composition comprising essentially anoxide of a hydrogenating'metal selected from the group consisting ofiron, nickel, cobalt, copper, silver, tin, cadmium, lead, and bismuthcombined with an oxide of a metalgqselected from the group consisting ofchromium, molybdenum, tungsten, vanadium,

and uranium, under a superatmospheric pressure and at a temperature inexcess of 80 C.-

18. A process of hydrogenating unsaturated fatty oils, comprisingpassing hydrogen into a liquid body of the oil to be hydrogenated andhaving in suspension a catalyst composed of metallic nickel intimatelyassociated with and adherently supported on chromium oxide and formed byreduction of a substance having substantially the empirical formulaNlzCrzOs.

19. A process of hydrogenating unsaturated fatty oils, comprisingpassing hydrogen into a liquid body of the oil to be hydrogenated andhaving in suspension a catalyst composed of metallic nickelintimately'associated with and adherently supported on chromium oxideand formed by reduction of a nickel-chromite.

20. A process of hydrogenating unsaturated fatty oils, comprisingpassing hydrogen into a liquid body of the oil to be hydrogenated andhaving in suspension a catalyst composed of metallic nickel intimatelyassociated with and adherently supported on chromium oxide and formed byreduction of a nickel chromium-oxygen compound corresponding empiricallyin composition to nickel chromite and having a nickelchromium ratio of1:1.

'21. The process. of hydrogenating an organic compound which isstructurally capable of hydrogenation, comprising contacting such compound in the liquid phase in the presence of a catalyst comprisingessentially chromium oxide chemically combined with copper.

22. The process of hydrogenating an organic compound which isstructurally capable of hydrogenation, comprising contacting such com.-pound in the liquid phase in the presence 01' hydrogen with a catalystwhich is prepared by heating copper chromate to its decompositiontemperature, whereby the chromate is decomposed to a chromite.

23. The method of making nickel catalyst for hydrogenation ofunsaturated fatty oils and the which comprises reacting furfural in theliquid like which comprises preparing a nickel chromate from an aqueoussolution containing a nickel sulfate and a soluble chromate, thoroughlywashing the precipitate with water, heating the pre- 5 cipitated nickelchromate to convert the chromate to chromite and reducing such chromiteat superatmospheric temperature with hydrogen.

24. The process for the hydrogenation of furfural which comprisesheating a mixture oi! Im- 10 fural, water and hydrogen, while inintimate contact with a hydrogenation catalyst, to a temperature of 80to 110 C. and under a hydrogen pressure of 1400 pounds per square inch,said hydrogenation catalyst being prepared by re- 15 ducing nickelchromate to nickel chromite with hydrogen at a temperature of 450 to500? C. 25. The process of hydrogenating furfural which comprisesreacting furfural in .the liquid state with hydrogen in the presence ofa catalyst 20 prepared by partially reducing nickel chromate. 26. Theprocess of hydrogenating furfural state with hydrogen in the presence ora catalyst comprising essentiallynickel chromite.

27. The process of hydrogenating furfural which comprises reactingfurfural in the liquid state with hydrogen in the presence of a catalystprepared by heating nickel chromate to a temperature of 400 C. and thenreducing the resulting compositionwith hydrogen at 500 C. p

28. The process of hydrogenating iurfural which comprises reactingturfural in the liquid state with hydrogen under a superatmosphericpressure 29. The process of hydrogenating furfural which comprisesreacting furfural in the liquid state with hydrogen under asuperatmospheric pressure and in the presence of a catalyst comprisingessentially nickel chromite.

WILBUR A. LAZIER.

and in the presence or a catalyst prepared by partially reducing nickelchromate.

